Language Languages are perhaps the most basic and critical extension type. Languages are packaged as either a core language pack or an extension language pack. These packages consist of INI files which contain key/value pairs. These key/value pairs provide the translation of static text strings within Joomla! source code. This allows both the Joomla! core and third party components and modules to be internationalised. Core language packs also include an XML meta file describing the language and providing information about the fonts to use for PDF content generation. Reference: http://docs.joomla.org/Glossary
Search engine optimization (SEO) The process of optimizing your pages to give them high-ranking placement in the search results page of a search engine (SERP) - including Google, Bing, Yahoo and other search engines.
SQL Stands for Structured query language. The language used to create SQL queries to access and manipulate databases. Includes DDL (data-definition language that manages table and index structure) and DML (data manipulation lan- guage, the subset of SQL used to add, update and delete data).
